Introduction to Overhead Line: Electric power can be transmitted or distributed either by means of underground  cables or by overhead line. The underground cables are rarely used for power transmission due to two main reasons. Firstly, power is generally transmitted over … (Read More)

Conductor Material Used for Transmission and Distribution: The conductor is one of the important items as most of the capital outlay is invested for it. Therefore, proper choice of material and size of the conductor is of considerable importance. The Commonly … (Read More)

Line Support: The supporting structures for overhead line conductors are various types of poles and towers called line support. In general, the line supports should have the following properties : High mechanical strength to withstand the weight of conductors and wind loads … (Read More)

Types of Insulators in Transmission Lines: The overhead line conductors should be supported on the poles or towers in such a way that currents from conductors do not flow to earth through supports i.e., line conductors must be properly insulated from … (Read More)

Potential Distribution Over Suspension Insulator String: A string of suspension insulator consists of a number of porcelain discs connected in series through metallic links. Fig. 8.10 (i) shows 3-disc string of suspension insulator. The porcelain portion of each disc is in … (Read More)

String Efficiency of Insulator: As stated above, the voltage applied across the string of suspension insulators is not uniformly distributed across various units or discs. The disc nearest to the conductor has much higher potential than the other discs. This unequal … (Read More)

Corona: When an alternating potential difference is applied across two conductors whose spacing is large as compared to their diameters, there is no apparent change in the condition of atmospheric air surrounding the wires if the applied voltage is low. However, … (Read More)

Sag in Overhead Transmission Lines: While erecting an Sag in Overhead Transmission Lines, it is very important that conductors are under safe tension. If the conductors are too much stretched between supports in a bid to save conductor material, the stress … (Read More)

Mechanical Principles in Transmission Lines: Mechanical Principles in Transmission Lines design should depend to some extent on the importance of continuity of operation in the line under consideration. In general, the strength of the line should be such as to provide against … (Read More)